It was a typical bodybuilding regimen: back squats, leg presses, leg extensions, bench presses, shoulder presses, lat pulldowns, and cable rows. Each workout, they did three sets of eight to twelve reps of each exercise, lifting to failure.

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The only difference between the two groups: One rested for one minute between sets, and the other rested for three minutes.

After eight weeks, the researchers used ultrasound imaging to measure the lifters’ muscle growth.

The men who had rested longer had more growth in all the muscles tested: the biceps, triceps, and quads.

We’re not talking about monster gains: The longer-resting group grew an extra 1.2 to 3.5 millimeters in each muscle. But those millimeters come from such an easy tweak that few guys who are trying to bulk would turn them down.

The researchers also tested the subjects’ strength gains by determining their one-rep max in the bench press and back squat. The longer resters won this contest, too.

They increased their one-rep max for the squat by 15.2 percent and for the bench by 12.7 percent. That’s compared to the one-minute rest group, which increased its maxes by 7.6 percent and 4.1 percent, respectively.

That’s big: If you can bench 180 pounds, a lifting regimen with longer rests could help you increase that to 203 pounds in eight weeks. Resting for only 1 minute between sets, on the other hand, could hold you back to only 187 pounds.

Why the difference? The researchers think that a longer rest period allows you to recover more fully between sets, which may enable you to lift heavier weights in your next set, says lead study author Brad Schoenfeld, Ph.D. Those heavier weights put more tension on your muscles, which may lead to bigger gains in both strength and size.

How Long to Rest Between Sets

Consider working longer rests into your routine if you want to build strength and size, says Schoenfeld.

This study only compared one-minute and three-minute rests, but other research suggests that two minutes may be enough to fully recover between sets, he says.

Take those two-minute rests after your major compound exercises like squats, presses, and rows, which are more physically taxing and take longer to recover from.

But you can stick to shorter, 60-second rests for single-joint movements like biceps curls, which you’ll bounce back from more quickly.